hp 40gs_user's guide_English_E_HDPMSG40E07A

Computer Algebra System (CAS) 14-47

DIVIS

Gives the divisors of an integer.

Example

Typing:

DIVIS(12)

gives:

12 OR 6 OR 3 OR 4 OR 2 OR 1

Note: DIVIS(0) returns 0 OR 1.

EULER

Returns the Euler index of a whole number. The Euler

index of n is the number of whole numbers less than n that

are prime with n.

Example

Typing:

EULER(21)

gives:

Explanation: {2,4,5,7,8,10,11,13,15,16,17,19} is

the set of whole numbers less than 21 and prime with 21.

There are 12 members of the set, so the Euler index is12.

FACTOR Decomposes an integer into its prime factors.

Example

Typing:

FACTOR(90)

gives:

2·3

·5

GCD

Returns the greatest common divisor of two integers.

Example

Typing:

GCD(18, 15)

gives:

hp40g+.book Page 47 Friday, December 9, 2005 1:03 AM